1. Field of the Invention
The present invention relates to electro-optic panels having marks, such as alignment marks and marks for process control, and to manufacturing methods therefor. In addition, the present invention relates to electro-optic devices comprising electro-optic panels. Furthermore, the present invention relates to electronic apparatuses comprising the electro-optic devices.
2. Description of the Related Art
Display devices have been widely used for mobile apparatuses and information display terminals at home, in offices and/or at worksites, in cars, and the like. In particular, liquid crystal display panels have features such as being thin and lightweight and using low voltage and having low power consumption. Recently, since the need for even lower power consumption has increased, the use of reflective liquid crystal display devices has increased. A reflective liquid crystal display device is a liquid crystal device provided with a reflective layer so as to utilize incident light thereon from the outside as a light source. The reflective liquid crystal device has a liquid crystal display panel.
Hereinafter, a liquid crystal display panel used for the reflective liquid crystal device will be described. FIG. 16 is a schematic plan view showing a liquid crystal display panel.
A liquid crystal display panel 600 has a first substrate 610 and a second substrate 620.
The first substrate 610 and the second substrate 620 oppose each other. At a predetermined side edge portion (lower side in FIG. 16) of the liquid crystal display panel 600, the first substrate 610 is disposed so that an edge portion thereof protrudes toward the outside from an edge portion of the second substrate 620. That is, the first substrate 610 has a portion (hereinafter referred to as a xe2x80x9cprotruding portion of the first substratexe2x80x9d) 612 at which the first substrate 610 does not overlap the second substrate 620.
At a side edge portion (left side in FIG. 16) adjacent to the side edge portion of the liquid crystal display panel 600 described above, the second substrate 620 is disposed so that an edge portion thereof protrudes toward the outside from an edge portion of the first substrate 610. That is, the second substrate 620 has a portion (hereinafter referred to as a xe2x80x9cprotruding portion of the second substratexe2x80x9d) 622 at which the second substrate 610 does not overlap the first substrate 610.
At predetermined locations on the first protruding portion 612 and the second protruding portion 622, alignment marks 670 are formed.
FIG. 17 is a schematic cross-sectional view of the part taken along the line Bxe2x80x94B in FIG. 16.
At the periphery between the first substrate 610 and the second substrate 620, a sealing member 632 is formed. Since the sealing member 632 is formed, a predetermined gap (hereinafter referred to as a xe2x80x9ccell gapxe2x80x9d) 630 is maintained between the first substrate 610 and the second substrate 620. In addition, in the cell gap 630, liquid crystal is enclosed, whereby a liquid crystal layer 634 is formed.
The surface of the first substrate 610 opposing the second substrate 620 is formed to have an irregular surface 614. The irregular surface 614 is so formed in order that light for display will be scattered so as to increase the viewing angle. In addition, on the irregular surface 614, a reflective layer 640 is formed. The shape of the upper surface of the reflective layer 640 conforms to the irregular surface thereunder. On the reflective layer 640, a layered structure [laminate] (not shown) composed of a transparent electrode, an alignment film, and the like is formed.
On the surface of the second substrate 620 opposite the first substrate 610, a retardation film 684 and a polarizer 686 are formed. On the surface of the second substrate 620 opposing the first substrate 610, a layered structure (not shown) composed of a transparent electrode, an alignment film, and the like is formed.
On the irregular surface 614 in the protruding portion 612 of the first substrate 610, the alignment marks 670 are formed. FIG. 18 is an enlarged schematic view of B in FIG. 17.
As shown in FIG. 18, when the alignment marks 670 are formed on the irregular surface 614, the upper surfaces 674 of the alignment marks 670 conforms to the shape of the irregular surface 614. In the case in which the first substrate 610 and a flexible circuit board (not shown) are aligned with each other, when the upper surfaces 674 of the alignment marks 670 are irregular, problems may occur.
The alignment mentioned above is performed by detecting light emitted from a light source (not shown) by, for example, a CCD camera (not shown). The light source and the CCD camera are disposed at locations opposing the alignment marks 670. In the case in which the upper surfaces 674 of the alignment masks 670 are irregular, when the alignment is performed, as shown in FIG. 18, the light is scattered at the upper surfaces 674 of the alignment marks 670, and hence, the image detected by the CCD camera is blurred. consequently, the alignment marks 670 are difficult to be visually detected using the CCD camera. As a result, alignment is difficult to perform when the alignment marks 670 are formed as described above.
An object of the present invention is to provide an electro-optic panel in which visual detection of a mark can be performed properly [optically] and to provide a manufacturing method therefor.
Another aspect of the present invention is to provide an electro-optic device and an electronic apparatus, which include the electro-optic panel.
An electro-optic panel of the present invention comprises, a first substrate and a second substrate opposing each other, in which the first substrate has a protruding portion formed so that an edge portion thereof protrudes toward the outside from an edge portion of the second substrate, and in which a surface of the first substrate opposing the second substrate has an irregular surface, a planarized layer provided on the irregular surface in the protruding portion; and a mark provided on the planarized layer.
In this context, the mark is an alignment mark or a mark for process control.
According to the electro-optic panel of the present invention, the visual [or optical] detection of the mark can e performed properly.
Hereinafter, the reasons for this will be described. In the electro-optic panel of the present invention, the mark is formed on the planarized layer. Accordingly, at the upper surface of the mark, light scattering can be reduced. As a result, the visual detection of the mark can be performed properly. Consequently, according to the electro-optic panel of the present invention, compared to the case of an electro-optic panel in which the mark is formed on an irregular surface, for example, the alignment of the electro-optic panel with a flexible circuit board can be performed with high precision.
In addition, in the electro-optic panel of the present invention, the alignment mark is formed above the protruding portion. Accordingly, the electro-optic panel of the present invention is particularly useful, for example, when the alignment of a circuit board for connection (for example, a flexible circuit board) or a driver IC with the electro-optic panel is performed.
The electro-optic panel described above can be preferably used as a liquid crystal panel. In addition, the electro-optic panel can be more particularly used as a reflective liquid crystal panel and as a transflective liquid crystal panel.
The material for the planarized layer is not specifically limited; however, the material is preferably similar to that for the first substrate in terms of an optical characteristic. The optical characteristic mentioned above is refractive index. In addition, the similarity of the optical characteristic means that the values of the refractive indexes thereof are close to each other. As a material used for the planarized layer, acrylic resins, polyimide resins, polyamide resins, polyacrylic amide resins, and polyethylene terephthalate resins may be mentioned as examples.
As a material used for the mark, the material is not specifically limited so long as the mark can be visually [or optically] detected, and for example, a material primarily composed of indium tin oxide, aluminum, silver, chromium, tantalum, or nickel may be mentioned.
An electro-optic panel may have one of the structures described below.
(1) First, the electro-optic panel may further comprise an electrode layer formed on the first substrate, in which the electrode layer and the mark may be composed of the same material. Since the material for the electrode layer is the same as that for the mark, the electrode layer and the mark may be formed in the same step. As a material mentioned above, a material primarily composed of indium tin oxide, tantalum, aluminum, silver, chromium, or nickel may be mentioned as an example.
(2) The electro-optic panel may further comprise a reflective layer formed on the first substrate, in which the reflective layer and the mark may be composed of the same material. Since the material for the reflective layer is the same as that for the mark, the reflective layer and the mark may be formed in the same step. As a material mentioned above, a material primarily composed of aluminum, silver, chromium, or nickel may be mentioned as an example.
Furthermore, the electro-optic panel may have the structure described below.
The electro-optic panel described above may further comprise a coloring layer and a protective layer for protecting the coloring layer, in which the planarized layer and the protective layer may be composed of the same material.
Since the planarized layer and the protective layer are composed of the same material, the planarized layer and the protective layer may be formed in the same step.
The electro-optic panel of the present invention can be manufactured by, for example, the following method.
The method for manufacturing an electro-optic panel comprising a first substrate and a second substrate opposing each other, in which the first substrate has a protruding portion formed so that an edge portion thereof protrudes toward the outside from an edge portion of the second substrate, and in which a surface of the first substrate opposing the second substrate is an irregular surface, the method comprising the following steps (a) and (b):
(a) a step of forming a planarized layer on the irregular surface in the protruding portion; and
(b) a step of forming a mark on the planarized layer.
In this context, the mark is an alignment mark or a mark for process control.
According to the method for manufacturing the electro-optic panel, since the mark is formed on the planarized layer, a preferable mark, which can be visually detected, may be formed.
Preferable applications of the electro-optic panels obtained by the manufacturing method therefor described above are equivalent to those described in the section related to Electro-Optic Panel.
Materials used for the planarized layer and for the mark are similar to those described in the section Electro-Optic Panel.
The method for manufacturing the electro-optic panel described above may be performed in accordance with one of the methods described below.
(1) First, a method for manufacturing an electro-optic panel may further comprise a step of forming an electrode layer on the first substrate, in which the mark and the electrode layer may be formed in the same step. In the method described above, as a material used for the mark and the electrode layer, a material primarily composed of indium tin oxide, tantalum, aluminum, silver, chromium, or nickel may be mentioned as an example.
(2) Second, a method for manufacturing an electro-optic panel may further comprise a step of forming a reflective layer on the first substrate, in which the mark and the reflective layer are formed in the same step. In the method described above, as a material for the mark and the reflective layer, a material primarily composed of aluminum, silver, chromium, or nickel may be mentioned.
In addition, the method for manufacturing an electro-optic panel may be performed in accordance with a method described below.
That is, the method for manufacturing an electro-optic panel may further comprise a step of forming a coloring layer on the first substrate and a step of forming a protective layer for protecting the coloring layer, in which the planarized layer and the protective layer may be formed in the same step.
The electro-optic device of the present invention comprises the electro-optic panel according to one of the above. These electro-optic devices can be manufactured at, for example, a higher yield due to the advantages of the electro-optic panel.
The electronic apparatus of the present invention comprises the electro-optic device according to the above. This electronic apparatus can be manufactured at, for example, a higher yield due to the advantages of the electro-optic device.